A weather strip that is designed to prevent appearance degradation, designed to prevent a decrease in sealing properties, and designed to prevent a decrease in sound insulating properties at a peripheral section of a sashless door opening. In particular, the weather strip (1) includes a base, a seal lip section (first seal lip section (12)) and a protruding section (13) supporting the seal lip section (first seal lip section (12)) in a state where a door opening is closed.